1. Technical Field
The invention relates to certain compounds having therapeutic utility and to processes for their preparation. More particularly, the present invention relates to salts of 2-(6-{2-[(2R)-2-methyl-1-pyrrolidin-1-yl]-ethyl}-2-naphthalen-2-yl)-2H-pyridazin-3-one, which demonstrates histamine-3 receptor ligand activity.
2. Description of Related Technology
Histamine-3 receptor ligands are recognized modulators of neuronal activity. One active agent, 2-(6-{2-[(2R)-2-methyl-1-pyrrolidin-1-yl]-ethyl}-2-naphthalen-2-yl)-2H-pyridazin-3-one, has been described as demonstrating histamine-3 modulating activity. 2-(6-{2-[(2R)-2-Methyl-1-pyrrolidin-1-yl]-ethyl}-2-naphthalen-2-yl)-2H-pyridazin-3-one has the structure
and is a useful therapeutic agent for treating a variety of histamine-3 mediated conditions and diseases. The compound also can have the name 2-(6-{2-[(2R)-2-methyl-1-pyrrolidinyl]ethyl}-2-naphthyl)-3(2H)-pyridazinone. The active agent is further described in at least U.S. patent application Ser. No. 10/689,735, filed on Oct. 22, 2003. The compound is stable at room temperature and can be isolated as a low melting point solid having a melting point of 58° C.
Salts of 2-(6-{2-[(2R)-2-methyl-1-pyrrolidin-1-yl]-ethyl}-2-naphthalen-2-yl)-2H-pyridazin-3-one that demonstrate crystalline properties are particularly beneficial for formulation of the active agent. Moreover, it would be particularly beneficial to identify forms of the 2-(6-{2-[(2R)-2-methyl-1-pyrrolidin-1-yl]-ethyl}-2-naphthalen-2-yl)-2H-pyridazin-3-one active agent that demonstrate crystalline properties and are characterized by improved stability and a melting point higher than the 2-(6-{2-[(2R)-2-methyl-1-pyrrolidin-1-yl]-ethyl}-2-naphthalen-2-yl)-2H-pyridazin-3-one active agent. Isolated forms of 2-(6-{2-[(2R)-2-methyl-1-pyrrolidin-1-yl]-ethyl}-2-naphthalen-2-yl)-2H-pyridazin-3-one demonstrating such properties would be particularly beneficial for preparing pharmaceutical formulations useful for preventing and treating histamine-3 mediated diseases and disorders.